The present invention relates to ovens for preparing food and in particular to a “combination” oven that may cook food with steam and convection airflow and that further provides for the adjustment of peak oven heating power.
High-end commercial ovens may provide for multiple cooking modes including heat augmented with forced airflow (convection) and heat augmented with steam. Generally, convection cooking uses a fan to disrupt the insulating effect of stagnant air around the food, increasing the heat flow to the food. This increased peak flow may be used, for example, to promote surface browning of the food. In contrast, the application of steam (typically also with operation of the convection fan) can provide for fast cooking while retaining food moisture, flavors, and nutrients. Steam cooking generally prevents surface browning. These different modes may be combined in sequence during a cooking cycle, for example, to rapidly cook meat and then to brown its surface.
Different heat sources are commonly used for ovens including electrical heating elements, which employ electrical current passing through a resistance in communication with the oven cavity, and gas heating elements, which provide for the combustion of gas and the circulation of the combustion exhaust through a heat exchanger in communication with the oven cavity. Temperature control of the oven is typically provided by switching the electrical current or the gas on and off according to a sensed temperature of the oven cavity. Such switching between on and off states greatly simplifies the control of the electrical current and gas elements.
Ovens of this type are commercially available from the Alto-Shaam Inc. of Menomonee Falls, Wis. and are described generally in U.S. Pat. No. 6,188,045, entitled “Combination Oven with Three Stage Water Atomizer” hereby incorporated by reference.
The speed with which an oven can attain a given temperature when loaded with food is normally determined by the peak power that may be delivered to the heating element when the heating element is continuously operating. Normally, this peak power of the heating element is selected to effect a desired trade-off between energy usage and oven performance.
The need to compromise between energy usage and oven performance can be relaxed by the use of the so-called “turbo” mode in which the peak power of the heating element is adjusted. Turbo mode may be desired when fast cooking speeds are of great importance.